Vulnerabilidad en Linux (CVE-2023-54265)

En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:<br /> <br /> ipv6: Corrige un error de acceso a variable no inicializada en __ip6_make_skb()<br /> <br /> Syzbot informó un error como sigue:<br /> <br /> =====================================================<br /> BUG: KMSAN: uninit-value in arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline]<br /> BUG: KMSAN: uninit-value in arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline]<br /> BUG: KMSAN: uninit-value in atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline]<br /> BUG: KMSAN: uninit-value in __ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956<br /> arch_atomic64_inc arch/x86/include/asm/atomic64_64.h:88 [inline]<br /> arch_atomic_long_inc include/linux/atomic/atomic-long.h:161 [inline]<br /> atomic_long_inc include/linux/atomic/atomic-instrumented.h:1429 [inline]<br /> __ip6_make_skb+0x2f37/0x30f0 net/ipv6/ip6_output.c:1956<br /> ip6_finish_skb include/net/ipv6.h:1122 [inline]<br /> ip6_push_pending_frames+0x10e/0x550 net/ipv6/ip6_output.c:1987<br /> rawv6_push_pending_frames+0xb12/0xb90 net/ipv6/raw.c:579<br /> rawv6_sendmsg+0x297e/0x2e60 net/ipv6/raw.c:922<br /> inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827<br /> sock_sendmsg_nosec net/socket.c:714 [inline]<br /> sock_sendmsg net/socket.c:734 [inline]<br /> ____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476<br /> ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530<br /> __sys_sendmsg net/socket.c:2559 [inline]<br /> __do_sys_sendmsg net/socket.c:2568 [inline]<br /> __se_sys_sendmsg net/socket.c:2566 [inline]<br /> __x64_sys_sendmsg+0x367/0x540 net/socket.c:2566<br /> do_syscall_x64 arch/x86/entry/common.c:50 [inline]<br /> do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> La no inicialización fue creada en:<br /> slab_post_alloc_hook mm/slab.h:766 [inline]<br /> slab_alloc_node mm/slub.c:3452 [inline]<br /> __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491<br /> __do_kmalloc_node mm/slab_common.c:967 [inline]<br /> __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988<br /> kmalloc_reserve net/core/skbuff.c:492 [inline]<br /> __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565<br /> alloc_skb include/linux/skbuff.h:1270 [inline]<br /> __ip6_append_data+0x51c1/0x6bb0 net/ipv6/ip6_output.c:1684<br /> ip6_append_data+0x411/0x580 net/ipv6/ip6_output.c:1854<br /> rawv6_sendmsg+0x2882/0x2e60 net/ipv6/raw.c:915<br /> inet_sendmsg+0x101/0x180 net/ipv4/af_inet.c:827<br /> sock_sendmsg_nosec net/socket.c:714 [inline]<br /> sock_sendmsg net/socket.c:734 [inline]<br /> ____sys_sendmsg+0xa8e/0xe70 net/socket.c:2476<br /> ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2530<br /> __sys_sendmsg net/socket.c:2559 [inline]<br /> __do_sys_sendmsg net/socket.c:2568 [inline]<br /> __se_sys_sendmsg net/socket.c:2566 [inline]<br /> __x64_sys_sendmsg+0x367/0x540 net/socket.c:2566<br /> do_syscall_x64 arch/x86/entry/common.c:50 [inline]<br /> do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80<br /> entry_SYSCALL_64_after_hwframe+0x63/0xcd<br /> <br /> Esto se debe a que icmp6hdr no está en la región lineal de skb bajo el escenario del socket SOCK_RAW. Acceder a icmp6_hdr(skb)-&amp;gt;icmp6_type directamente activará el error de acceso a variable no inicializada.<br /> <br /> Usa una variable local icmp6_type para llevar el valor correcto en diferentes escenarios.